Probing robust Majorana signatures by crossed Andreev reflection with a quantum dot

Feng, Guan-Hao; Zhang, Honghao

doi:10.1103/physrevb.105.035148

Cited by 18 publications

(9 citation statements)

References 67 publications

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“…In addition to their advantages in topological quantum computing, multi QDs systems also present many novel phenomena in the tunneling of an electron [46][47][48][49][50][51]. Recently, the double QDs have attracted widespread attentions due to their ability to determine the conductance behavior when coupled to a topological superconductor (TSC) nanowire [52][53][54]. Furthermore, the interaction strength between the QDs may be used to tune the state of MF [55] and topological phase [56].…”

Section: Introductionmentioning

confidence: 99%

Resonant exchange of chiral Majorana Fermions modulated by two parallel quantum dots

Wu,

Liu,

Liu

et al. 2024

J. Phys.: Condens. Matter

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Resonant exchange of the chiral Majorana fermions (MFs) that is coupled to two parallel Majorana zeromodes (MZMs) or two parallel quantum dots (QDs) is investigated. We find that, in the two QDs couplingcase, the resonant exchange for the chiral MFs is analogous to that in the MZM coupling case. We furtherpropose a circuit based on topological superconductor (TSC), which is formed by the proximity coupling ofa quantum anomalous Hall insulator (QAHI) and a s-wave superconductor, to observe the resonant exchangeof chiral MFs pairs. The numerical calculations show that the resonant transmission of the chiral MFs can beadjusted by varying the coupling parameters. It is particularly noteworthy that, by only modulating the couplingstrength between the two QDs, the resonant exchange may be switched on or off. By adding another MZM, thenon-Abelian braidinglike operation can be realized. Therefore, our design scheme may provide another way fornon-Abelian braiding operation of MFs and the findings may have potential application value in the realizationof topological quantum computers.

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Section: Introductionmentioning

confidence: 99%

Resonant exchange of chiral Majorana Fermions modulated by two parallel quantum dots

Wu,

Liu,

Liu

et al. 2024

J. Phys.: Condens. Matter

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“…An attractive quantum transport alternative to the mean value of a current flowing through a nanoscopic setup is to study the random deviations of this current from its mean value, that is the current fluctuations, characterized, for example, by the shot noise S > . Here majority of Majorana shot noise proposals assume nonequilibrium states originating from bias voltages [54][55][56][57][58][59][60][61][62][63][64] and explore the behavior of S > (V ) at small and large V . As in mean current experiments, where the differential conductance ∂I(V )/∂V provides an access to an averaged Majorana universality, the differential shot noise ∂S > (V )/∂V allows one to reveal a universal fluctuation behavior governed by Majorana entangled states.…”

Section: Introductionmentioning

confidence: 99%

Majorana differential shot noise and its universal thermoelectric crossover

Smirnov

2023

Phys. Rev. B

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Nonequilibrium states driven by both electric bias voltages V and temperature differences ∆T (or thermal voltages eVT ≡ kB∆T ) are unique probes of various systems. Whereas average currents I(V, VT ) are traditionally measured in majority of experiments, an essential part of nonequilibrium dynamics, stored particularly in fluctuations, remains largely unexplored. Here we focus on Majorana quantum dot devices, specifically on their differential shot noise ∂S > (V, VT )/∂V , and demonstrate that in contrast to the differential electric or thermoelectric conductance, ∂I(V, VT )/∂V or ∂I(V, VT )/∂VT , it reveals a crossover from thermoelectric to pure thermal nonequilibrium behavior. It is shown that this Majorana crossover in ∂S > (V, VT )/∂V is induced by an interplay of the electric and thermal driving, occurs at an energy scale determined by the Majorana tunneling amplitude, and exhibits a number of universal characteristics which may be accessed in solely noise experiments or in combination with measurements of average currents.

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“…One of the most reliable signatures of MBSs is the observation of the zero-energy state exhibited as a zero-bias abnormal peak in the electric differential conductance [15], whose peak value should reach its quantized maximum of 2e 2 /h. However, some other mechanisms, such as Andreev bound states (ABSs) due to disorder [16][17][18][19], quantum dots (QD) on nanowires [20][21][22][23] or the Kondo effect [24], may also induce a zero-bias conductance abnormality that is stable with respect to the experimental parameters. Further signatures expected for MBSs are phase-coherent transport of the quasiparticles, the 4π Josephson effect and the topological Kondo effect [24].…”

Section: Introductionmentioning

confidence: 99%

“…In such structures, MBSs in a superconductor hybridize with each other and form ABSs [26,27]. It is well known that ABSs are states arising in semiconductors in close proximity, leading to a sharp configuration of the density of states within the energy gap in the superconductors [17][18][19][26][27][28][29][30][31][32]. There are various platforms to generate these subgap states, such as semiconductor QDs coupled to a superconductor.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of the Josephson Current in a Quantum Dot Connected to Majorana Nanowires

Chi¹,

Jia²,

Liu

et al. 2023

Nanomaterials

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We investigate the behavior of the Josephson current in a system composed of a quantum dot (QD) sandwiched between two nanowires by using the nonequilibrium Green’s function technique. We consider that the nanowires are in proximity to s-wave superconducror substrates, and Majorana bound states (MBSs) are induced at their ends. It is also assumed that the two nanowires are not aligned in the same orientation, but form a bent angle with respect to each other. It is found that when only one spin state on the QD is coupled to the left nanowire, the Josephson current is the typical sinusoidal function of the phase difference between the two nanowires. If both spin states hybridize to the MBSs with equal coupling strengths, the Josephson current then is not a sinusoidal function of the phase difference. In particular, when the bent angle between the two nanowires is π/2 and the two modes of the MBSs in each nanowire are decoupled from each other, the Josephson current is enhanced by about twenty times in magnitude as compared to the former case. Moreover, the simultaneously enhanced currents of the two spin directions are of the same magnitude but flow in opposite directions and they induce a large pure spin current. Our results also show that this abnormally enhanced Josephson current will be suppressed by a vertical magnetic field applied to the QD.

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Probing robust Majorana signatures by crossed Andreev reflection with a quantum dot

Cited by 18 publications

References 67 publications

Resonant exchange of chiral Majorana Fermions modulated by two parallel quantum dots

Resonant exchange of chiral Majorana Fermions modulated by two parallel quantum dots

Majorana differential shot noise and its universal thermoelectric crossover

Enhancement of the Josephson Current in a Quantum Dot Connected to Majorana Nanowires

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